1. Technical Field
Improved heating systems are disclosed for variety of pumps including, but not limited to, magnetic drive pumps, mechanical seal pumps other types of internal gear pumps and external gear pumps as well. More specifically, combination heat and temperature control systems for integration into existing pumps are also disclosed for the support and control of pipeline heat tracing.
2. Description of the Related Art
Certain applications require external heat sources to be applied to a process system, including one or more pumps of a process system, to maintain a required temperature and/or to enable desired flow rates of the material being processed. Currently available heaters for pumps include cartridge heaters, platen heaters, tubing coils and blanket or jacket heaters.
Cartridge heaters may be used to heat inlet or outlet piping or the pump casing and to regulate pump or material temperature. There are several limitations to the use of cartridge heaters. First, because of the bulk of the typical cartridge heater, there is a substantial distance between the heater and the material to be heated and pumped. The long heat transfer path means longer heat up times, which is compounded by the large thermal mass of a cartridge heater, the inevitable radiation heat loss and limitations on power density or heat flux when the cartridge heater is distanced from the material to be heated and pumped. Furthermore, cartridge heaters often require a high precision intermediate thermal conducting layer to improve the contact between the heater and the component surrounding the material to be heated. This additional layer, which often is in the form of a precious metal layer, and adds significantly to the cost of the pump. Finally, cartridge heaters can be placed in limited locations within a pump due to geometry and space constraints. Thus, cartridge heaters are limited in their use on pumps of process systems.
Platen heaters are used to heat a plate-like body which can be attached to a pump casing or base structure. For example, platen heaters are commonly used in diffusion pumps, which, in turn are used for high and ultra high vacuums. A platen heater is typically provided in a plate attached below the base of the outer body of a diffusion pump. Similar to cartridge heaters, because of the bulk of the typical platen heater and the bulk of the plate, there is a significant distance between the platen heater and the fluid to be heated. The long heat transfer path means longer heat up times, which is compounded by the large thermal mass of a typical platen heater and the base of the pump. Platen heaters, like cartridge heaters, can only be placed in limited locations due to geometry and space constraints.
Other techniques for heating pumps include the use of steam or hot oil and tubing wrapped around one or more pump components. Obviously, these strategies add significantly to the overall bulk of the pump design and are impractical in applications where space is limited and in mobile applications where access to steam or hot oil is limited or not available.
Blanket or jacket heaters are cumbersome and bulky. Further, these types of add-on heaters must often be disposed a substantial distance from the material to be heated and therefore require long heat up times and are limited in terms of control and accuracy.
As a result, there is a need for improved heaters or heating elements that can be incorporated into a variety of pumps, including existing pumps that avoids the disadvantages associated with cartridge heaters, platen heaters and heat exchangers.